Direct Scaling of Measure on Vortex Shedding through a Flapping Flag Device in the Open Channel around a Cylinder at Re∼103: Taylor's Law Approach.

The problem of vortex shedding, which occurs when an obstacle is placed in a regular flow, is governed by Reynolds and Strouhal numbers, known by dimensional analysis. The present work aims to propose a thin films-based device, consisting of an elastic piezoelectric flapping flag clamped at one end, in order to determine the frequency of vortex shedding downstream an obstacle for a flow field at Reynolds number Re∼103 in the open channel. For these values, Strouhal number obtained in such way is in accordance with the results known in literature. Moreover, the development of the voltage over time, generated by the flapping flag under the load due to flow field, shows a highly fluctuating behavior and satisfies Taylor's law, observed in several complex systems. This provided useful information about the flow field through the constitutive law of the device.

Assessment of coastal vulnerability to land-based sources of pollution and its application in Apulia, Italy.

The present paper deals with the assessment of the coastal vulnerability to pollution sources induced by land-based activities (LBAs). The coastal vulnerability is expressed and evaluated in relation to the land-based activities present in the coastal areas and a new index, namely Coastal Pollution Index from land-based activities (CPI_LBAs), is proposed. The index is calculated considering nine indicators using a transect-based approach. The nine indicators refer to point and non-point sources of pollution, and include: rivers quality status, seaports category, airports category, wastewater treatment facilities/submarine outfalls, aquaculture/mariculture areas, pollution load of urban runoff, type of artisanal/industrial facilities, farm/agriculture areas, type of suburban roads. Each indicator is quantified by means of quantitative scores, whereas the strength of cause-effects relationship is assessed by assigning weights using the Fuzzy Analytic Hierarchy Process approach (F-AHP). The indicators are then aggregated to obtain a synthetic index and classified in five categories of vulnerability. The main findings of this study include: i) the identification of key indicators of coastal vulnerability to LABs; ii) the development of a new index to identify the coastal transects where the effects of the LBAs may be the greatest. The paper explains the methodology for the index computation, and illustrates it with an application in Apulia, Italy. The results demonstrate the feasibility of the index and its usefulness to identify the most critical areas in terms of land pollution sources and to produce a vulnerability map. The application allowed to have a synthetic picture of the threat of pollution from LBAs, facilitating its analysis and the benchmarking between the transects. Regarding the case study area, results show that low vulnerability transects are characterized by small agricultural areas/artisanal activities and small urban areas, whereas in very high vulnerability transects all indicators assume high scores.

Improvement of a coastal vulnerability index and its application along the Calabria Coastline, Italy.

The present paper further develops a coastal vulnerability index formulation (CVI) previously proposed by the authors by integrating a new variable and redefining three variables to improve the suitability of the index for low-lying coasts. Eleven variables are divided into three typological groups: geological, hydro-physical process and vegetation. The geological variables are: geomorphology, shoreline erosion/accretion rates, coastal slope, emerged beach width, and dune. The hydro-physical process group includes: river discharge, sea-level change, mean significant wave height and mean tide range. The vegetation variables are: vegetation behind the back-beach and coverage of Posidonia oceanica. The index was applied to a stretch of the Ionian coast in the province of Crotone in the Calabria region (Southern Italy), and a vulnerability map was produced. A geography information system (GIS) platform was used to better process the data. For the case study area, the most influential variables are shoreline erosion/accretion rates, coastal slope, emerged beach width, dune, vegetation behind the back-beach, and coverage of Posidonia oceanica. The most vulnerable transects are those near urban areas characterized by the absence of dunes and vegetation. Statistical and sensitivity analyses were performed, and the proposed CVI was compared with the previous formulation proposed by the authors and with two other CVI methods present in the literature.

Multivariate sea storm hindcasting and design: the isotropic buoy-ungauged generator procedure.

The present work provides indications for assessment of wave climate and design of structures at sea at ungauged sites, both critical issues in Ocean sciences. The paper is of methodological nature and of global worldwide applicability. It shows how suitable wave hindcasting relations can be exploited in order to provide sea storm scenarios at an ungauged (Target) location useful for design purposes: in particular, only geographical information and the knowledge of another gauged (Source) buoy are used. Several are the novelties introduced. (i) New hindcasting relations are derived. (ii) A full statistical model is set up for the Target area, whereas traditional hindcasting simply transfers time series from a gauged to an ungauged site: this gives the possibility to appropriately deal with design and hazard assessment at the Target location. (iii) The multivariate behavior of non-independent random variables is properly modelled by using the Theory of Copulas. As an illustration, a number of case studies is investigated, involving four pairs of buoys which, given their positions and exposures, are representative of a wide variety of sea states and conditions, as well as of different wave generation mechanisms.